Improvement in the art of marking sheet-metal plates



H. W001). Art of Marking Sheet-Metal Plates.

No. 199,135. Patented Jan. 8, 1878.

ALAN woon no.

PHI PHIA HOWARD WOOD, OF OONSHOHOOKEN, ASSIGNOR TO ALAN WOOD & 00.,

OF PHILADELPHIA AND OONSHOHOOKEN, PENNSYLVANIA.

IMPROVEMENT IN THE ART OF MARKING SHEET-METAL PLATES.

Specification forming part of Letters Patent No. 199,135, dated January 8, 1878 application filed October 22, 1877.

To all whom it may concern:

Be it known that I, HOWARD W001), of Conshohocken, Montgomery county, Pennsylvania, have invented a new and useful Improvement in the Art of Marking Sheet-Metal Plates, of which the following is a speoification:

The object of my invention. is to rapidly and effectually form letters or other characters on plates of sheet metal, an object which I attain in the following manner, reference being had to the accompanying drawings, in which Figure 1 is a view of a plate of sheet metal marked according to my invention; and Fig. 2, a sectional view illustrating the manner in which my invention is carried into effect.

Ihave discovered that if a hot plate of sheet metal be allowed to cool in contact with a cold body of metal, having upon its surface letters or other characters sunken or in relief the parts of the plate which are in direct contact with the raised portions of the body of metal will 0001 more rapidly, and acquire a deeper shade of color than the remainder of the plate, so that when the plate is cold the letters or other characters will be permanently marked upon its surface.

In practically carrying out my invention, I prefer to treat the plates of sheet metal after they come from the annealing-furnace, and to form the letters or other characters on or in the straightening-bed B, on which the plates are usually laid, as shown in Fig. 2, the straightening and marking operations being thereby conducted simultaneously.

I claim as my inventionl. The mode herein described of forming letters or other characters on sheet-metal platesthat is to say, by allowing the hot plates to cool in contact with a metal surface, having the letters or other characters sunken in or formed in relief upon it, as set forth.

2. The combination of a plate for straightening sheet-iron with letters or other characters, sunken or in relief, as set forth, for the purpose specified.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HOWARD WOOD.

Witnesses ALFRED CRAFT, SAML. WYLIE. 

